When an astronaut goes to space, his immune system does not work as well in microgravity as on Earth.

“Knowing about the astronauts’ health may lead to new treatments on Earth for those with impaired immune systems,” the researchers noted in a NASA statement.

Two new studies called TripleLux-A and TripleLux-B on leucocytes or human defence cells seek to understand how these cells set up their mechanisms.

While TripleLux-A will test leukocytes in rats on the space station, TripleLux-B will explore how microgravity causes changes in cellular-level mechanisms.

“Our goal with TripleLux-B is to find out whether the cells of the immune system of a mussel – which is older in an evolutionary sense – are affected in the same way as those in the immune system of an astronaut – or, in this case, a rat,” said Peter-Diedrich Hansen, professor of toxicology at Germany’s Berlin Institute for Technology.

Cellular changes in the immune system would be examined in both the tests.

The tests would also separate the specific effects of microgravity from other space flight factors like radiation.

In our immune systems, large white blood cells called leucocytes are the first line of defence against infection.

These cells engulf foreign bodies and produce a burst of reactive oxygen that helps destroy invaders.